How to adjust b.c. to get ballistic chart to match drops

WA6.5x47

Member
Joined
Mar 12, 2021
Messages
5
Location
WA
I did a similar exercise recently. I shot from 200-600 yards in 100 yard increments. My LabRadar recorded a MV of 2980 with an SD of 11. I use a Silver Mountain Solo e-target and get velocities at the various distances shot. I can play with the muzzle velocity and BC to get the trajectory I recorded. Having the extra information on the velocity at distance is very helpful. I find it interesting that I always have to reduce the muzzle velocity to match the Solo velocity and drops. I assume this is due to the bullet wasting a bit of energy as it stabilizes after exiting the muzzle.
 

Lrreloader

Well-Known Member
Joined
Jun 18, 2019
Messages
885
Location
Pa
I didn't shoot that many shots at 1,000 could we remove that from equation, I was told 300 yards and in but want to be prepared for longer since the gun is capable. 100 yard zero, only thing I have to double check is scope height. Using only 300 and 600 values can it be corrected?
BrentM ?
 

skipglo

Well-Known Member
LRH Team Member
Joined
Jan 23, 2015
Messages
2,509
Location
Alberta
What if the MV isn’t exact and your adjusting for BC when it’s in fact MV’s off? Sorry maybe a dumb question, not sure.
Not a dumb question at all! I generally adjust velocities first from chrono results. Most manufacturers claim the others B.C.s are exaggerated or not true...I have no way of verifying BC but velocity I do! Maybe not the right way...but works for me
 

BrentM

Well-Known Member
Joined
Jan 10, 2013
Messages
3,227
Location
Meridian, Idaho
Yes. I show 2806 fps corrected. That is if the BC is right. Not that familiar with hammer but also at 600 and in BC doesn't have a large effect.

I used 1.87" scope height.
 

BPollard

Well-Known Member
Joined
Jul 16, 2020
Messages
159
Location
NJ
Triple check velocities and are you using target angle in your dope? Also is your scope true moa or Smoa? That could be as much as a foot and a half at 1000 yards
 

Lrreloader

Well-Known Member
Joined
Jun 18, 2019
Messages
885
Location
Pa
Yes. I show 2806 fps corrected. That is if the BC is right. Not that familiar with hammer but also at 600 and in BC doesn't have a large effect.

I used 1.87" scope height.
Can your program adjust bc? Not MV, MV was from labradar over alot of shots running consistent 2,780
 

BrentM

Well-Known Member
Joined
Jan 10, 2013
Messages
3,227
Location
Meridian, Idaho
Can your program adjust bc? Not MV, MV was from labradar over alot of shots running consistent 2,780
Can but using 2780 and .325 the dial up is 3.7 and 12.3. Literally dang near the same as your actual which most people will never shoot .1-.3 differences well enough to matter. That is without knowing your actual scope height. I run a vx6 as well but at 1.75" I used 1.87 as this more standard for the average person imho.
 

Aussie Hunter Steve

Well-Known Member
Joined
Aug 28, 2012
Messages
245
While it’s likely you just need to tweak the BC, are you also able to shoot at extended distances where you can just measure bullet drop and leave your scope set on zero- this will tell whether the scope is tracking accurately?
 

BrentM

Well-Known Member
Joined
Jan 10, 2013
Messages
3,227
Location
Meridian, Idaho
While it’s likely you just need to tweak the BC, are you also able to shoot at extended distances where you can just measure bullet drop and leave your scope set on zero- this will tell whether the scope is tracking accurately?
Just much better to do a tall tracking test. Less wasted ammo trying to shoot 1000 and fight environmentals.
 

BrentM

Well-Known Member
Joined
Jan 10, 2013
Messages
3,227
Location
Meridian, Idaho
Can your program adjust bc? Not MV, MV was from labradar over alot of shots running consistent 2,780
You can pm if you want to. I can send you some charts for different elevations etc you may encounter. Print and laminate the charts or get app. AB, Shooter, strelock pro.
 

orkan

Official LRH Sponsor
LRH Sponsor
Joined
Jun 11, 2010
Messages
911
Location
SD
Many of us use shooter due to the simplicity and accuracy of the program. I've used a pile and its one of the easiest to plug and play and lines up with AB quite well. AB is the best engine there is so.....
... you guys must shoot in some really calm places, because Shooter doesn't compute for aerodynamic jump. AB does.
 

Lrreloader

Well-Known Member
Joined
Jun 18, 2019
Messages
885
Location
Pa
That you for all the help as always, great site full of great people, I got enough for as far as I'm gonna shoot, I will sit down and play on computer tonight
 
Top